Clinical validation of an in-house quantitative real time PCR assay for cytomegalovirus infection using the 1st WHO International Standard in kidney transplant patients

Introduction:

Cytomegalovirus (CMV) is one of the most common agents of infection in solid organ transplant patients, with significant morbidity and mortality.

Objective:

This study aimed to establish a threshold for initiation of preemptive treatment. In addition, the study compared the performance of antigenemia with qPCR results.

Study design:

This was a prospective cohort study conducted in 2017 in a single kidney transplant center in Brazil. Clinical validation was performed by comparing in-house qPCR results, against standard of care at that time (Pp65 CMV Antigenemia). ROC curve analysis was performed to determine the ideal threshold for initiation of preemptive therapy based on the qPCR test results.

Results:

Two hundred and thirty two samples from 30 patients were tested with both antigenemia and qPCR, from which 163 (70.26%) were concordant (Kappa coefficient: 0.435, p<0.001; Spearman correlation: 0.663). PCR allowed for early diagnoses. The median number of days for the first positive result was 50 (range, 24-105) for antigenemia and 42 (range, 24-74) for qPCR (p<0.001). ROC curve analysis revealed that at a threshold of 3,430 IU/mL (Log 3.54), qPCR had a sensitivity of 97.06% and a specificity of 74.24% (AUC 0.92617 ± 0.0185, p<0.001), in the prediction of 10 cells/10⁵ leukocytes by antigenemia and physician's decision to treat.

Conclusions:

CMV Pp65 antigenemia and CMV qPCR showed fair agreement and a moderate correlation in this study. The in-house qPCR was revealed to be an accurate method to determine CMV DNAemia in kidney transplant patients, resulting in positive results weeks before antigenemia.

COVID-19 seroprevalence in military police force, Southern Brazil

Background

Limited data is available regarding the frequency of COVID-19 in populations that are highly exposed to SARS-CoV-2. In this cross-section study we evaluated COVID-19 seroprevalence in military police forces of 10 major cities in Rio Grande do Sul, South of Brazil.

Methods

Sampling was randomly performed in clusters, in respect to the number of professionals at service per city and military unit. Research subjects were evaluated on July 23, 2020 (first wave peak in Brazil). Clinical information was obtained, and venous blood was taken for ELISA testing (IgA, and IgG antibodies). Sample size consisted of 1,592 military workers (33.6% of study population). They were mostly man (81.2%) and young (median 34 years-old). Most had been asymptomatic (75.3%) during pandemic, and 27.5% reported close contact with COVID-19 cases (after a median time of 21 days). Antibodies were detected in 3.3% of the participants, mostly IgA (2.7%), and IgG (1.7%). After 3 weeks, 66.7% of IgA and IgG results turned negative, in addition to 78.3% and 100% of borderline IgA and IgG results, respectively.

Conclusion

The seroprevalence of COVID-19 amongst military police was at least 3.4 higher than the findings of other studies performed in the general population, in the same cities and dates. Most detectable antibodies were of IgA class, which implies recent exposure. Asymptomatic people were more prone to have negative antibody titters in the second run.

Candidaemia Mortality Has not Changed Over the Last 2 Decades in Brazil

Despite advances in fungal diagnostics and antifungal therapy, mortality associated with candidaemia remains very high, particularly in developing countries. In this study, we reviewed the Brazilian literature on candidaemia over the last 20 years (1999-2019), with the aim to document if mortality rates changed over the years in Brazil. Variables studied included number of patients with candidaemia per study, age, most prevalent Candida species and use of antifungals. Selected manuscripts evaluated a median of 114 patients, the majority being men (54.4%). Median age was 45 year-old. The most prevalent species in all studies was C. albicans (37.3%), followed by C. parapsilosis (23.0%). An increase in use of echinocandins occurred in recent years, with a proportional decrease in the use of fluconazole and amphotericin B. Surprisingly, mortality of candidaemia has remained unchanged over the years in the largest Latin American country, regardless of treatment with echinocandins. Potential explanations for these findings are discussed.

Structure-based design of δ-lactones for new antifungal drug development: susceptibility, mechanism of action, and toxicity

Dermatophytes are the etiological agents of cutaneous mycoses, including the prevalent nail infections and athlete's foot. Candida spp. are opportunistic and emerging pathogens, causing superficial to deeper infections related to high mortality rates. As a consequence of prolonged application of antifungal drugs, the treatment failures combined with multidrug-resistance have become a serious problem in clinical practice. Therefore, novel alternative antifungals are required urgently. δ-Lactones have attracted great interest owing to their wide range of biological activity. This article describes the antifungal activity of synthetic δ-lactones against yeasts of the genus Candida spp. and dermatophytes (through the broth microdilution method), discusses the pathways by which the compounds exert this action (toward the fungal cell wall and/or membrane), and evaluates the toxicity to human leukocytes and chorioallantoic membrane (by the hen's egg test-chorioallantoic membrane). Two of the compounds in the series presented broader spectrum of antifungal activity, including against resistant fungal species. The mechanism of action was related to damage in the fungal cell wall and membrane, with specific target action dependent on the type of substituent present in the δ-lactone structure. The damage in the fungal cell was corroborated by electron microscopy images, which evidenced lysed and completely altered cells after in vitro treatment with δ-lactones. Toxicity was dose dependent for the viability of human leukocytes, but none of the compounds was mutagenic, genotoxic, or membrane irritant when evaluated at higher concentrations than MIC. In this way, δ-lactones constitute a class with excellent perspectives regarding their potential applications as antifungals.

Biofilm Antifungal Susceptibility of Candida Urine Isolated from Ambulatory Patients

Justificativa e objetivos: a associação entre as formações biofilme uma resistência antifúngica foi sugerido para ser um fator importante na patogênese de diversas espécies de Candida. Além disso, estudos têm incluído candidíase invasiva de pacientes hospitalizados; no entanto, existem poucos estudos que avaliaram a distribuição das espécies, suscetibilidade aos antifúngicos e formação de biofilme de espécies de Candida isoladas de pacientes ambulatoriais. Assim, o objetivo deste estudo foi avaliar se a produção de biofilme contribui para a resistência antifúngica em Candida isoladas de amostras de urina obtidas de pacientes de ambulatório. Métodos: Durante um ano, 25 amostras de urina positivas para leveduras, foram coletadas, armazenadas e semeadas em agar Sabouread suplementado com cloranfenicol e deixadas a temperature ambiente por 5 dias, para posterior identificação: 52% (13/25) foram C. albicans, 36% (9/25) C. tropicalis, 8% (2/25) C. krusei e 4% ( 1/25) C. parapsilosis. Resultados: A capacidade de formar biofilme foi detectada em 23 (92%) da levedura estudados e 15,4% (2/13) de C. albicans foram fluconazol (FLU) e cetoconazol (PET) resistente, enquanto que 11,1% (1/9 ) de C. tropicalis foram resistentes cetoconazol e foram anidulafungina (ANI) não-suscetíveis. Conclusão: nossos resultados mostraram a alta capacidade de formação de biofilme entre Candida isoladas de pacientes ambulatoriais. Conclusão: nossos resultados mostraram a alta capacidade de formação de biofilme entre Candida isoladas de pacientes ambulatoriais.